1. Field of the Invention
The present invention relates to an organic light emitting display apparatus, and more particularly, to an organic light emitting display apparatus having a touch panel function and a photo sensor with increased light sensitivity.
2. Description of the Related Art
Developments in display technology have led to the replacement of conventional display devices with portable, thin flat panel display devices. Among the flat panel display devices, electroluminescent display devices, which are self-emissive display devices, have wide viewing angle, high contrast ratio, and high response speed, and thus have been considered as the next-generation display devices. In addition, an organic light-emitting display device having a light emitting layer formed of an organic material has improved properties in terms of brightness, driving voltage, and response speed in comparison to an inorganic light emitting display device, and can realize multiple colors.
Researches are in progress to develop organic light emitting display devices with touch panel functions. In one approach, a display screen having a touch panel function is mounted on an organic light emitting display apparatus so that a command can be input by touching the display screen with a finger or a pen device. The touch panel display screen used in this case includes a photo sensor.
However, in an organic light emitting display apparatus having a conventional touch panel function, light cannot be sensed properly when there is an inadequate amount of light due to dark surroundings. To address this problem, a method of sensing light using internal light emitted from an organic light emitting diode has been developed. In order to realize a touch panel function, the light emitted from the organic light emitting diode needs to be emitted to the outside of a panel and reflected by the finger of the user, and be incident on the photo sensor. However, some of the light rays emitted from the organic light emitting diode are not emitted to the outside of the panel and reflected by the finger of the user, but are directly incident on the photo sensor. Accordingly, the light sensitivity of the photo sensor is not totally reliable. So even when a user does not touch the display screen, internal light can still be sensed and malfunctions can occur, thereby increasing product defects and user's inconvenience.